Biome stability and fragmentation under critical environmental temperature change

Critical phenomena in the climate system can cause drastic changes in the state of planetary ecosystems as well the entire biosphere. There also are mechanisms through which the biosphere can make an effect on climate. In this manuscript, we study the nonlinear dynamics of the interaction of the climate system with the biosphere by linking an energy balance climate model to different species competition models. We develop an asymptotic approach to these models and investigate how migration strengthens biome stability and biodiversity. Moreover, we derive relations describing biome boundary shifts under global warming (or cooling) and check those relations against paleo data on plant biome location. Finally, the models demonstrate that critical rates of changes in the environmental temperature dynamics may shift biome stability

Geohimicheskaja harakteristika donnyh otlozhenij v zone pokmarkov v vostochnoj chasti Finskogo zaliva [The geochemical characteristics of the bottom sediment in the pockmark area of the eastern part of the Gulf of Finland]

It is the first time pockmark-like structures have been detected in the south-eastern part of the Gulf of Finland with the help of a side-scan sonar and a profile recorder. The analysis of the distribution of microcomponents in the bottom sediment indicates that the pockmark area is located in the geochemical barrier border zone where the reducing medium of the incoming mineralized solution meets the highly oxidizing sea water medium. The hydrodynamic and geochemical processes in the pockmark zone create focal areas of anomalous microenvironment and affect the composition and development of benthos

Status and trends in the structure of Arctic benthic food webs

On-going climate warming is causing a dramatic loss of sea-ice in the Arctic Ocean and it is projected that the Arctic Ocean will become seasonally ice-free by 2040. Many studies of local Arctic food webs now exist and with this review paper we aim to synthesize these into a large-scale assessment of the current status of knowledge on the structure of various Arctic marine food webs, and their response to climate change, and to sea-ice retreat in particular. Key drivers of ecosystem change and potential consequences for ecosystem functioning and Arctic marine food webs are identified along the sea-ice gradient with special emphasis on the following regions: seasonally ice free Barents and Chukchi Seas, loose ice pack zone of the Polar Front (PF) and Marginal Ice Zone (MIZ), and permanently sea-ice covered high Arctic. Finally, we identify gaps existing in the knowledge of different Arctic marine food webs and provide recommendations for future studies